The primary objective of this project is the development of sensitive behavioral and developmental tasks in order to detect subtle effects of low dose pesticide exposure. Toxic effects of pesticides may be manifested as subtle behavioral disturbances long before any classical symptoms of poisoning become apparent. Any change of behavior may indicate or even predict, later, more severe consequences. Early detection of toxic effects may attenuate or possibly prevent harm to humans and other organisms. A compounding factor in pesticide exposure studies is the considerable evidence that exposure to chemicals while immature is more likely to produce toxic effects than exposure as an adult. The chemicals to be assessed in the proposed study possess the ability to cross the placental and blood brain barriers. Dieldrin and toxaphene are both widely used and accumulate in the environment. Chlordimeform has been found to affect the behavior of various organisms. The emphasis of the proposed research is the long term evaluation of rats exposed both prenatally and post natally to low doses of dieldrin, chlordimeform, toxaphene, and the two most toxic fractions of toxaphene, Toxicant A and Toxicant B. A variety of behavioral and maturational measures will be utilized at different periods in the animal's lifespan. The wider range of behavioral analyses greatly increases the discriminative power of any behavioral research. The undersigned agrees to accept responsibility for the scientific and technical conduct of the project and for provision of required progress reports if a grant is awarded as the result of this application.